1. Field of the Invention
This invention has relation to cranes having upper works rotatably supported on lower works and more specifically to quick removal and assembly structures for allowing rapid disassembly of the upper works from the lower works preparatory to transporting the crane from one work location to another and for allowing quick assembly of the upper works back onto the lower works upon arrival of the disassociated parts of the crane at the new location for use.
2. Description of the Prior Art
Before the advent of quick removal and assembly structures, anti-friction bearings rotatably supported and connected cranes upper works to their lower works. For example, an outer race of such an anti-friction bearing was bolted to an upper works using a plurality of extremely heavy bolts and nuts of great strength and size which had to be torqued up very accurately and tightly, and the inner race was bolted to the lower works using similar bolts. In order to disassemble the upper works from the lower works, one or the other sets of these bolts and nuts had to be removed. This was time consuming and costly, because the bolts have to be thrown away after one use. This is necessary because each bolt loses a substantial amount of its strength after having been fully torqued up. For example, after having been torqued up five times, the bolt strength is less than 30% of its original.
The expired patent to Bargmann, U.S. Pat. No. 3,061,389, granted Oct. 30, 1962, illustrates the prior art. Power crane platform or upper works 1 is affixed to an outer race 8,9 by a plurality of nut and bolt assemblies 14 while supporting platform or lower works 2 is bolted to an inner race 7 of an anti-friction bearing by a plurality of nut and bolt assemblies 12. To disassemble upper works 1 from lower works 2, either all of the nut and bolt assemblies 14 must be removed, or, more likely, all of the nut and bolt assemblies 12 must be removed. This latter procedure will allow the entire anti-friction bearing to be removed from the lower works 2 long with the upper works 1. After the crane sections or works have been transported to the new location for use, the upper works had to be lowered toward the lower works, and the bolt holes in the inner race 7 had to be lined up with the bolt holes in the lower works 2 before brand new nut and bolt assemblies 12 could be installed. It is to overcome this costly and time consuming procedure that quick removal and assembly structures have been developed.
It is well known to have circumferentially and concentrically spaced teeth extending downwardly from a crane upper works arranged to interdigitate with circumferentially and concentrically spaced teeth extending upwardly from the lower works of a crane, and to provide some means of locking these teeth with respect to each other to firmly, fixedly, but temporarily lock the upper works with respect to the lower works so that the crane can be used for its intended purpose.
For example, in the patent to Petrik et al, U.S. Pat. No. 3,921,817, an upper works of a crane is supported on an anti-friction bearing which has an outer race member secured to a lower works. The inner race member of the bearing surrounds a mounting ring which depends from the upper works. The upper works mounting ring and the inner race members have teeth which can move past each other when the upper works is being assembled to the lower works. After being so assembled, when shifted in relative angular position, these teeth serve to lock the upper works to the lower works. When shifted to the original angular position, these teeth again are in clearing relation to other, and the upper works can be removed from the lower works. Power rams effect relative angular shifting of the toothed members with respect to each other.
Use of a clamping ring to fixedly position the interdigitated ends or fingers or teeth of interfitted members is shown in the expired patent to Gilbert, U.S. Pat. No. 2,710,763, granted on June 14, 1955, and in the expired patent to Troeger, U.S. Pat. No. 2,553,220, granted on May 15, 1951.
In the Gilbert patent, teeth or fingers 14 of a circumferential flange 9 secured to an engine casing 10 are adapted to mesh with teeth or fingers 15 of a circumferential flange member 16 secured to a housing 18. A clamp ring 8 fits into mutually aligned external grooves 20 and 21 in these teeth to lock the flanges with respect to each other. Also, circumferential grooves 23 and 24 are provided on the inner circumference of the teeth 14 and 15, respectively, and a resilient split ring 27 having a free diameter slightly larger than the inner diameter of grooves 23 and 24 is utilized to temporarily hold the teeth 14 and 15 in mesh until the clamp ring 8 can be secured in position.
Similarly, in the Troeger patent, "a resilient ring-like element or split ring 44" locks teeth 22 and 24 together by fitting into recesses 34 and 36 provided in those teeth.
It is also known to support upper works fixedly but temporarily with respect to lower works by providing a downwardly extending cylindrical mounting ring on an upper works to be received into an upwardly extending cylindrical mounting ring on the lower works, and then locking the two together through the use of opposing circumferential grooves in the mounting rings.
For example, in the patent to Jensen et al, U.S. Pat. No. 3,923,407, granted Dec. 2, 1975, the inner race member of an anti-friction bearing which is rotatably mounted with respect to a lower works receives an upper mounting ring which is mounted on an upper works. Opposing circumferential grooves in the mounting ring and the inner face member receive a locking ring which is expanded and contracted by a power actuator mounted with respect to the upper works. When the locking ring bridges the grooves, the upper works is locked to the lower works. When the locking ring is contained entirely in the groove of the upper mounting ring, the crane upper works is released from the lower works for separation of the works from each other.
A similar structure is shown in the expired to Eaton, U.S. Pat. No. 2,877,732, which shows intermeshing "mounting rings" or axially aligned tubular sections 12 and 13 having aligned opposing circumferential grooves or channels 16 and 17, respectively. A locking ring or expansible split ring 20 is disposed within the channels 16 and 17 when sections 12 and 13 are locked to each other. When the locking ring 20 is entirely within the groove or channel 16, the sections 12 and 13 can be removed from each other.
The patent to Hanes et al, U.S. Pat. No. 3,521,911, discloses another form of locking ring to be positioned entirely within one of two mating grooves when the two telescoped cylindrical elements of the device are unlocked and to bridge the gap between these two mating grooves when the device is to be locked.
The patents cited above and the patents listed immediately below include all of the prior art located in a search of the prior art and include other patents which were cited as references in the patents located in the search. The patents listed below are not believed to be particularly pertinent to the invention.
______________________________________ U.S. Pat. Nos. ______________________________________ 1,052,439 Crosby February 4, 1913 1,473,935 Horton November 13, 1923 3,844,127 Koop, Jr. et al October 29, 1974 3,888,357 Bauer et al June 10, 1975 ______________________________________
Neither the inventor nor those in privity with him are aware of any prior art which is closer than that discussed above nor of any prior art which anticipates the claims herein.